Power Operations/Watershed Management
One of the most significant strategic advantages an aluminum smelter can have is reliable access to cost-effective electricity, produced with a low environmental impact. Major capital investments on Rio Tinto Alcan’s part – made on the basis of agreements with the provincial government of the day – secured such a source of electricity for the company’s B.C. operations.
Rio Tinto Alcan BC constructed and maintains a widely dispersed network of reservoir and power generation infrastructure that capitalizes on the topography of northern B.C. to generate an average of some 790 megawatts of hydroelectricity annually.
The Kenney Dam is the starting point. This rock-filled, clay-core structure impounds the waters of an inter-connected chain of lakes that make up the approximately 90,000-hectare Nechako Reservoir.
To regulate water levels, both within the reservoir and downstream of its natural outflow points on its eastern side, Rio Tinto Alcan BC operates the Skins Lake Spillway. And at Tahtsa Narrows, on the western side of the reservoir, it operates an intake through which water is directed into a 16-km tunnel running through the Coast Mountain Range.
The tunnel connects with penstocks with a 900-metre vertical drop, through which water passes to spin the turbines in the Kemano power station. Its eight massive generators are situated within chambers carved out of Mount Dubose. The electricity is then transmitted to the Kitimat smelter via more than 80 kilometres of power lines that traverse the 1,500-metre Kildala Pass.